Abstract
Fragmentation processes of highly excited neutral and charged atomic metal clusters are studied in the framework of an equilibrium statistical model. In the particular case of hot (near and above melting) neutral and charged sodium clusters of 100 and 200 atoms, a microcanonical Metropolis sampling is used to compute mass (or charge) correlation functions as a function of the excitation energy. This method allows to take the strong anharmonicities in the internal phonon spectrum realistically into account which are linked to the internal structural changes like melting. It is found that, at high enough excitation energy, the system exhibits a phase transition. This phase transition is specific for fragmenting finite systems. From the shape of the caloric curve one sees that the two phases involved are connected by a van der Waals loop characterizing a first order phase transition. Here we observe an enhanced fission and multifragmentation into two or more charged clusters with more than 10 atoms each. Various fragment correlations are studied.
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References
de Heer, W.: Rev. Mod. Phys.65, 611 (1993)
Brack, M.: Rev. Mod. Phys.65, 677 (1993)
Rayleigh, F.R.S.: Phil. Mag.14, 184 (1882)
Car, R., Parrinello, M.: Phys. Rev. Lett.55, 2471 (1985)
Barnett, R.N., Landman, U., Rajagopal, G.: Phys. Rev. Lett.67, 3058 (1991)
López, M.J., Jellinek, J.: Phys. Rev. A50, 1445 (1994)
Weisskopf, V.F.: Phys. Rev.52, 295 (1937)
Wearasinghe, S., Amar, F.G.: J. Chem. Phys.98, 4967 (1993)
Bertsch, G., Oberhofen, N., Stringari, S.: Z. Phys. D20, 123 (1991)
Hervieux, A.P., Gross, D.H.E.: Z. Phys. D33, 295 (1995)
Brink, D.M., Stringari, S.: Z. Phys. D15, 257 (1990)
Labastie, P., Whetten, R.L.: Phys. Rev. Lett.65, 1567 (1990)
Zhang, X.Z., Gross, D.H.E., Xu, S.Y., Zheng, Y.M.: Nucl. Phys. A461, 668 (1987)
Gross, D.H.E.: Rep. Progr. Phys.53, 605 (1990)
Bréchignac, C., Cahuzac, Ph., Carlier, F., de Frutos, M., Leygnier, J.: Chem. Phys. Lett.189, 28 (1992)
Knopse, O., Schmidt, R., Engel, E., Schmidt, U.R., Dreizler, R.M., Lutz, H.O.: Phys. Lett. A183, 332 (1993)
Pacheco, J.M., Ekardt, W.: Phys. Rev. Lett.68, 3694 (1992).
Röthlisberger, U., Andreoni, W.: J. Chem. Phys.94, 8129 (1991)
Poteau, R., Spiegelmann, F.: J. Chem. Phys.98, 6540 (1993)
Bréchignac, C., Cahuzac, Ph., Carlier, F., de Frutos, M.: Phys. Rev. B49, 2825 (1994)
Bréchignac, C., Cahuzac, Ph., Carlier, F., de Frutos, M., Leygnier, J.: J. Chem. Phys.93, 7449 (1990)
Bréchignac, C., Cahuzac, Ph., Carlier, F., de Frutos, M., Leygnier, J.: J. Chem. Soc. Faraday Trans.86, 2535 (1990)
Lian, L., Su, C.X., Armentrout, P.B.: J. Chem. Phys.97, 4072 (1992)
Lian, L., Su, C.X., Armentrout, P.B.: J. Chem. Phys.97, 4084 (1992)
Näher, U., Göhlich, H., Lange, T., Martin, T.P.: Phys. Rev. Lett.68, 3416 (1992)
Krappe, H.J.: Z. Phys. D23, 269 (1992)
Andrews, G.E.: Encyclopedia of mathematics and its applications. Addison-Wesley, reprinted by Cambridge University Press 1976
Poteau, R., Spiegelmann, F., Labastie, P.: Z Phys. D30, 57 (1994)
Rubinstein, R.Y.: Simulations and the Monte-Carlo method. New York: Wiley 1981
Perdew, J.P.: Phys. Rev. B37, 6175 (1988)
Borelius, G.: Solid State Phys.6, 1 (1963)
Hultgren, R., Orr, R.L., Anderson, P.D., Kelley, K.K.: Selected values of thermodynamic properties of metals and alloys. New York: Wiley 1963
Gross, D.H.E., Zhang, X.Z., Xu, S.Y.: Phys. Rev. Lett.56, 1544 (1986)
Hüller, A.: Z. Phys.93, 401 (1994)
Silberstein, J., Levine, R.D.: J. Chem. Phys.75, 5735 (1981)
Carlier, F.: PhD-thesis, University of Orsay, France 1991
Bréchignac, C., Cahuzac, Ph., Carlier, F., Leygnier, J., Roux, J. Ph.: J. Chem. Phys.102, 1 (1995)